Outcomes of Solar Surface Penetration Injuries Studied

Hoof sole penetration injuries are no small matter, though they might be nearly indiscernible to the eye and affect a small area. It’s more about what’s going on deep inside the hoof, where concealed damage to internal structures can be disastrous; the prognosis for horses injuring these structures to return to their prior athletic level is often bleak, and some horses might even require euthanasia if sepsis takes hold.

“The term ‘solar foot penetration’ can be used to describe a number of injuries, ranging from a simple nail prick following farriery and injuries involving just the horn of the foot and the digital cushion, through to deep injuries involving important structures such as the tendons and joints within the foot,” explained Judith Findley, BSc, BVM&S, Cert AVP (ES-O), MRCVS, of the University of Liverpool, in England. “Our study focused solely on those injuries which involved the joints and bursa of the foot (synovial structures).”

The team analyzed data from 95 cases with penetrating injuries to the coffin joint, navicular bursa, or digital flexor tendon sheath at four veterinary hospitals in the United Kingdom, and found that only 56% of the horses survived treatment and were discharged. Of those recovering to discharge, 57% returned to pre-injury athletic function. In total, only 36% of horses in this study returned to full performance ability.

Findley said the study results also showed that:

Injuries to the center of the frog had worse outcomes than those at either side of the frog;

Horses that required more than one surgery to treat a foot penetration were less likely to return to athletic function, possibly due to the effects of ongoing inflammation in the joints; and

Cobs, drafts, and ponies were more likely to return to their pre-injury level of athletic function than Thoroughbreds, Warmbloods, and Arabians, perhaps attributable to a lower baseline level of athletic function or higher tolerance to low-grade lameness in cold-blooded breeds.

“Solar foot penetrations involving the joints are potentially career and even life-threatening injuries,” said Findley, adding that the study's findings indicate the more time that lapses between injury and veterinary treatment, the more dire the outcome. “As the time increases, the likelihood of short-term survival and the likelihood of returning to the same level of athletic function decreases, therefore prompt treatment and early referral is very important. Foot penetrations located in the region of the frog should be treated as potentially serious and should be investigated by a veterinarian.”